Nozzle-control mechanism for steam turbines



H. T. HERR NOZZLE CONTROL MECHANISM FOR STEAM TURBINES June .16, 1925. 1,542,3s1

Filed Jan. 5, 192-3 2 Sheets-Sheet 1 INVENTOR 1 ATTORNEY June 16, 1925.

H. T. HERR NOZZLE CONTROL MECHANISM FOR STEAM TURBINES Filed Jan. 5, 1923 2 Sheets-Sheet 2 V INVENTOR ATTORNEY Patented June 16, 1 92 5.

HERBERTQT -HERRiEOFQPHILKDELRHIA, BENNSYLVANIA', essienon rol wnszrme HOUSE. ELECTRIC $AND MANUFAGTURING COMPANY, A I CORPORATION or ENN SYLV'ANIA.

NozzL'E co'ri'rnoi. ix'rnciinnisivz ron "STEAM m imniiins.

Applicationfiled ifaniiary 311923. Serial ilo. I

To "allt bizoni'itmayj ea mm: A I

Be it fknowirthat I, Brenner TIfHn'Rn', a citizen of the" United'states', anda' resident of Phileidelphia; in the countyof Phil adelphiit and state of Pennsylvania, have invented a new and useful Improvement in Nozzle' -Control Mechanism "for Steam Tur bines, lot "(which the following is a $13601- My invention relates "to elastic fluid tu'r bines and it has for 'its' object to provide im} proved means for cutting in out nozzles whereby variations in load my be readily taken careof. 1 i 1 A further object or "mYHnvention i to provide a' pl urality of nozzle groups, under the control l of suitable governor mechanism, so that the groups'and the nozzle" passages thereof are covered end uncdvered i one at atime and in succession in ordeifto take careof varyingpowerdemands. r. p p *Apparatus made accordancef wlth my invention is'illustrated'in the acco'inpeiiying drawings'formin'g a part of thi'sfip'plia- 10 1, in whiclrFig. 'lis a section'al' view of a. turbine showing my improved nozzle control' epparatusapplied thereto Fig; 2 is a sectional view taken along-the line"- I I I I of Fig. 1; 3 is. a fragmentary detailof a portion of my improvednozzle 'control apparatirsfandFigtA; is sectional'view taken along the line IV-IV of Figs. 1 andEZ. k It is common practicefln connectionwith turbines of the impulsetype, to cutin or out nozzles to take careof varying power requirements; 'It is the object of my invention; to provide apparatus of this character which is simple" in construction,

l'lighly responsive to changes in power requirements, andtwhich *is economical bothfrom the standpoint of manufacture and from" that o,f"operationl Infaccordance withimy inventiom I provide '11 'primarygroup of fnozzles whichere n; all times open tothe st m chest andsecondery and tertiary groups: of nozzles whichare adapted to be opened and closed one'at a timejan'd in successi'on'with {respect toethe ste'ani' chest, the nozzle openings of the secondary and tertiarv groups being opened and closed in succession,'whereby variations in joiverrequireinents may be taken care'of with a highdegree' of flexibility.

The apparatus for opening and closing the nozzle openings of 'the secon dary" and tertiary groups is operated by a suitable governor. If the powerdevelope'd by the norme-lly open groupof nozzles is insuffi cient, then the nozzles of the seconda'ry group are successively openedin order to rotor 11 providedwith suitable energy ab:-

retracting elements including a iirs't impulse stage, at '12. Theturbine casing is provided with an interior nozz'leboxor steam chest :13 having asuitable'steam' inlet '14, a pri mary group or block of nozzles15 consteiitly open to the blading of the stage i 12," and second ary and tertiary groups or blocks of nozzles 16 and'i17 which are adapted to be opened successively in accordance with the power requirementsf With the nozzle groups 16 and 17 closed, it the demand "for power should increase5 the nozzles ofthe secondary group are successively openedto meet the increased power demand; Further demands for power may result-in the o pening otall the nozzles of Y the secondary group andthen in the successive opening of thenozzles of'thetertiary group 17. I p

The secondary and tertiary group ofnozzles l6 and 17 areprovided withsimilar valveconstructions in order to secure the menim and closure of the nozzle oassa es p D .v 2:

in the "manner just referred to. The valve constructions including'fiexible webs 20 attached at their upper ends to the nozzlebox by any suitable means, for exam'ple by the bolts 2l,' and the lower ends ofthe webs are secured to the lower ends'of curved rockers 22." With thisconstruction, if 'a rocker is The rockers 22 of the secondary and tertiary groups of nozzles 16 and 17, respectively, are operated in a successive manner by means of governor mechanism shown at. 23, operating preferably through a fluid relay at 24. The operating mechanism between the governor and the rockers 22 includes a leverage connection which assures the opening of the secondary group of nozzles first and then the opening of the tertiary group of nozzles.

The leverage connection consists of a link 25, which is operated from the governor, and which is pivotally connected, at 26, to a floating lever 27. One end of the floating lever 27 is pivotally connected, at 28, to a link 29, the lower .end of the latter being pivotally connected, at 30, to the crank arm 31 of the rocker 22 of the secondary group. The'other end of the lever 27 is pivotally connected, at 31, to a link 32, which is pivotally connected, at 33, to the crank arm 31 of the rocker 22 of-the tertiary group of nozzles. The pivotal connection 26 is arranged nearer to the pivotal connection 28 than to the pivotal connection 31 in order to assure that, upon upward movement of the rod 25, the rocker 22 of the secondary nozzle group shall be moved first in order to expose the nozzle passages thereof, the

a lever 27, during this operation, f'ulcruming about the pivotal connection 31. An abutment 35 is arranged above the lever 27 so that when the rocker 22 of the secondary nozzle group 15 has been moved so as to expose all of the nozzle passages thereof, the lever 27 will then fulcrum about the abutment 35 with the result that, if further upward movement of the link or rod 25 takes place, the rocker 22 of the tertiary nozzle group 17 is moved upwardly in order to expose the nozzle passages thereof. Upon a decrease in power, the rocker 22 of the tertiary nozzle group 17 moves downwardly to close the tertiary nozzles; and, after the tertiary nozzles are closed, the rocker 22 of the secondary nozzle group 16 moves downwardly to close the nozzle passages thereof.

The specific valve construction of the secondary and primary nozzle groups 16 and 17, is essentially the same so that a detailed description of one will suffice. As may be seen from Figs. 2, 3 and 4, the nozzle passages are preferably covered by means of a seat member 37 which is provided with perforations 38 above the nozzle passages. The provision of perforations in this way reduces losses incident to wire-drawing and the reticulated construction constitutes a support for the flexible web 20, thereby preventing the bulging and sticking of the web in the nozzle opening.

The rockers 22 are provided with convex surfaces 39 about which the webs 20 are wrapped when the rockers are moved in one direction. The webs 20 are secured to the lower ends of the rockers 22 by any suitable means, for example, the screws or bolts 40 so that, upon upward movement of the rockers, the webs are wrapped about the convex surfaces 39, with the resultthat the nozzle passages of the secondary and tertiary groups 16 and 17 are opened in the manner stated.

A chain construction is provided for each rocker member 22 in order to maintain the webs 2O taut and in firm engagement with the seats 37. Chains 41 are shown secured to the upper ends of the rockers 22, and they are provided with links 42 at their lower ends which pass through walls of the steam chest or nozzle box 13. Equalizing levers 43 have eyes which fit around the links 42 and nuts 44 are carried by the links below the levers 43 so that the chains 41 may be placed substantially in equal tension. The levers 43 possess suflicient inherent flexibility so that a satisfactory tensioning of the chains may be had.

As will appear from Figs. 2 and 4, the chains 41 are arranged to cooperate with seats 45, concentric with the convex surface 39, so that at least half of each chain projects above the convex surface 39 when in contact with its seat 45. Owing to the projection of the chains in this way, it is necessary to provide clearance therefor at the sides of the nozzle passages in order that a rocker member 22 and its web 20 may firmly engage a seat 37. Accordingly, therefore, the nozzle passages are, in part, provided in plate members 46 which are of sufficient thickness to provide the needed clearance for the chains. Vith this arrange ment of chains, the webs 20 are maintained taut and the tension of the chains has an effective component tending to maintain the rocker and the webs in firm engagement with the seats 37.

From the structure described, operation of apparatus made in accordance with my invention will be apparent. If the turbine is loaded beyond the capacity of the primary nozzle group 15, the nozzle passages of the secondary nozzle group 16 are successively opened in response to the governor 23. With further increases in load, more and more of the nozzle passages of the secondary group are opened until, at last, all of such nozzle passages are open. If the load should increase still further, the floating lever 27 fulcrums about the abutment 35 and the rocker 22 of the tertiary nozzle group 17 is moved to expose nozzle passages thereof. A decrease in load results in closure of the tertiary nozzles first and then the closure of the secondary nozzles.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of variousother changes and modifications, Without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In a turbine, the combination of a nozzle block having a plurality of nozzle open ings therein, a flexible member secured to one end of the block and adapted to cover and uncover the nozzle openings, a convexlyfaced rocker member secured to the other end of the flexible member and adapted,

- when rocked, to cause the flexible member to be wrapped or unwrapped thereaboutto un cover or cover said nozzle openings, and flexible members cooperating With said convexly-faced member laterally of said first flexible member to maintain. the latter taut and in contact with the nozzle block.

2. In a turbine, the combination of a nozzle block having a plurality of openings therein, a flexible member secured to one end of the nozzle block for covering and un covering the nozzle openings, a convexlyfaced rocker member to which the other end of the flexible member is secured, flexible members disposed laterally of the first flexible member and secured to the convexlyfaced member, and yieldable means cooperating with said laterally disposed flexible means, whereby the latter are placed in tension to maintain the first flexiblemember taut and in contact with the nozzle block.

3. In a turbine, the "combination of a nozzle block having a plurality of nozzle openings therein, a flexible member having one end secured in position adjacent to one end of the nozzle block for covering and uncovering the nozzle openings, a rocker member having central and lateral convex faces, the other end of the flexible member being secured in position to one end of the convcxly-faced member so as to register with the central convexly faced portion thereof, chain members secured to the other end of the rocker member and cooperating with the laterally-disposed convex faces, and means cooperating with said chain members adjacent to the other end of the nozzle block for placing the chain members yieldably in tension, whereby the flexible member is maintained taut and in contact with the nozzle block.

4. In a turbine, the combination of a nozzle block having a series of nozzle openings therein, a seat member secured thereto and having a plurality of perforations over each nozzle opening, and a rocker member cooperating with the seat member for successively covering and uncovering the perforations and nozzle openings.

5. In a turbine, the combination of a nozzle block having a series of nozzle openings therein, a seat member secured to the block and having a group of perforations over each nozzle opening, a flexible member for covering and uncovering the perforations and nozzle openings, and means cooperating with the flexible member for causing the latter to cover and uncover the nozzle openings in succession.

6. In a turbine, the combination of a plurality of substantially parallel nozzle blocks, each of which is provided with a plurality of nozzle openings, means for covering and uncovering the nozzle openings of each block, a lever connected to each of said means, and an actuating link connected to said lever nearer to one of the means than to the other, whereby, when said link is moved, one of said means will be operated and then the other in succession.

7. In a turbine, the combination of a plum rality of nozzle blocks each of which has a plurality of nozzle openings therein, flexible members secured adjacent to corresponding ends of the blocks, rocker members socured, respectively, to the opposite 'ends of the flexible members, means cooperating with each of the rocker members to maintain the flexible members taut and in contact with the nozzle blocks, links connected to each of the rocker members for rocking the latter, a lever pivotally connected to each of said links, and an actuating link pivotally connected to said lever at a point nearer to one of said rocker connecting links than to the other, whereby, the rocker members will be actuated one at a time and in succession to successively cover and uncover the nozzle openings of each nozzle block.

In testimony whereof, I have hereunto subscribed my name this 2nd day of January 1923.

HERBERT T. HERE. 

